The present invention relates to an apparatus for recording/reproducing a television signal, especially, a television signal with a video signal, a sound signal, a data signal, and additional data such as television program information multiplexed thereon. More particularly, the present invention relates to an apparatus for recording all or part of service information, which is one of the additional data in the multiplexed signal, and reading information required by the user from the recorded information, thereby enhancing processing speed and response to an operation required by the user.
Conventionally, for a broadcasting method in which video and data are multiplexed for transmission, a teletext system as disclosed in Japanese Non-examined Patent Publication Hei 4-15676 is known. However, because text information is transmitted on a particular line during a vertical retrace interval, the volume of data carried in such a way is limited, thereby making high-level data broadcasting difficult.
For broadcasting associated with video contents, conversation contents may be transmitted as data, which are decoded on the receiver side to be attached with a text for those who are hard of hearing. For broadcasting not directly associated with video contents, news, weather forecasting, program guide, and stock price information, for example, may be displayed. In any case, these broadcasting systems do not involve such information, which significantly change in its contents in an extremely short time.
Thus, the conventional data broadcasting represented by teletext is limited in the volume of data carried, thereby making it difficult to provide high-level broadcasting. This problem, among others, has brought about the current investigation into the realization of digital broadcasting. In digital broadcasting, a video signal, a sound signal, and service information (to enable automatic configuration of the receiver to demultiplex and decode the various streams of programs within the multiplex) in addition to a data signal are all converted to digital signals, which can be compressed by digital technology to a great extent, resulting in the multiplexing of four to six channels in the bandwidth of a single current channel.
In such digital broadcasting, signals for four to six channels can be multiplexed in the bandwidth of a single current channel as mentioned above, so that a total of several hundred channels can be easily implemented. Further, the digital technologies bring about a variety of new capabilities. For example, these new capabilities include direct selection by searching a displayed program table for a desired program, obtaining home shopping information to order a desired product, participating in a quiz show or a questionnaire asked by a discussion program, and near-on-demand service. In such digital broadcasting services, chances are greater than ever before for viewers to access these services, thereby requiring a quick response by the receiver to user operations. However, as the information transmitted to the receiver increases, the processing time for searching for necessary information and accessing the searched information becomes longer. Therefore, searching and accessing the information transmitted after a request is made by the user impairs quick response to user requests.
It is noted that the terminology used in the present application is in correspondence with the terminology found in the European Telecommunication Standard, entitled "Digital Broadcasting System for Television, sound and data services; specification for Service Information (SI) in Digital Video Broadcasting (DVB) Systems," Draft prETS 300 468, October., 1994, pgs. 1-62, which is hereby incorporated by reference.